THE EVOLUTION LIST

THE EVOLUTION LIST is a forum for commentary, discussion, essays, news, and reviews that illuminate the theory of evolution and its implications in original and insightful ways. Unless otherwise noted, all materials may be quoted or re-published in full, with attribution to the author and THE EVOLUTION LIST. The views expressed herein do not necessarily reflect those of Cornell University, its administration, faculty, students, or staff.

Saturday, April 29, 2006

Cornell Summer Session Evolution Courses

Several people have emailed me requesting information on the Cornell summer seminar on design and purpose in nature. In particular, there seems to be some confusion about the course title and description as it is listed in the online course catalog for the Cornell Summer Session. Here is a link to the page in which the course listing can be found (scroll down to Ecology and Evolutionary Biology/E&EB):

As you can see, the course description in the online catalog is very brief and pretty generic, and the course title ("Seminar in History of Biology") doesn't mention design or purpose. Fear not! This is the correct course listing for the now somewhat notorious "design/purpose in nature seminar."

And, of course, please consider taking my introductory evolution course as well! We will be covering some of the same topics, and will take a historical and philosophical approach to the science of evolution. The class is generally small enough so that there is plenty of interaction between students and instructors (I usually have a couple of graduate student TAs), and we learn a lot about evolution and its implications (and have fun doing it).

There will also be a "course blog", which will be announced on this website soon. Watch this space!

Cornell Daily Sun: Seminar Promises Intelligent Design Discussion

Prof. Allen MacNeill, biology, will be offering a course about Intelligent Design, entitled "Evolution and Design: Is there a Purpose in Nature?". The course will be offered seminar-style over the summer of 2006, through the ecology and evolutionary biology, history and science and technology studies departments as well as the biology and society program.

The syllabus requires texts from authors both for and against intelligent design and includes optional texts, one of which is by Charles Darwin.

MacNeill first came up with the theme for the seminar when brainstorming with Prof. Will Provine, ecology and evironmental biology, for topics for this summer's seminar class. MacNeill says that the idea was inspired by the Kitzmiller v. Dover case, in which the Dover Area School District in Dover, Pa. was sued for requiring the teaching of intelligent design in high school science classes.

MacNeill labels himself a "very vehement critic" of intelligent design but hopes to inspire debate and controversy in his classroom.

"I'm hoping I get people from both sides so that the discussion will be animated. The worst thing you can have is a dull seminar, which is what you have when people have the same belief or don't believe in anything," he said.

As part of the attempt to present both sides of the issue, MacNeill has also invited Hannah Maxson '07, president of the Intelligent Design and Evolution Awareness club, to help with the class. Questions from the students about books by Intelligent Design proponents will be fielded by Maxson. The class is currently capped at eighteen to keep it discussion-based, not a lecture, says MacNeill.

It appears that this is not MacNeill's first delve into the topic of Intelligent Design. MacNeill is also on the IDEA list-serve, keeps consistent email correspondence with the club, holds debates about the issue and has invited the IDEA president to give a lecture in one his classes last year. MacNeill describes his relationship with the IDEA club as an "agreement in a very courteous manner to disagree."

"I'm glad it's being offered," said Maxson. "Intelligent Design needs to be discussed more in academia and not just [as] some 'frightening political movement' that needs to be stopped."

Hannah is currently working with MacNeill to pull together intelligent design articles for the reading list. She's also been invited to the discussions once the class starts to help "provide a cogent case for Intelligent Design theory."

IDEA Executive Director Seth Maxson also gives approval, saying that this "is an example of Intelligent Design being accepted as an intriguing scientific theory by the wider academic community."

Enrollment prospects are also looking up. Seth claims to have already talked with a few students who plan to take the class.

"They all seem very excited," he said.

Despite said excitement, MacNeill appears to have been met with some skepticism from colleagues. Since announcing what his class will be about, MacNeill has received many questions and comments both from students and professors via his personal blog. "Evolutionary biologists tended to be more negative about the course [than Intelligent Design advocates]," MacNeill said.

MacNeill also said that two colleagues have stated that the course shouldn't be offered in biology.

"I respectfully disagree," he said. "Most people in biology have a strong opinion on this, mostly negative. The knee-jerk response is to call the other side ignorant or dishonest; my experience is that that doesn't address the issue."

Though MacNeill claims to be "strongly skeptical of Intelligent Design, at the very least", he says he is not worried about one-sided enrollment.

"What's exciting for me is people taking strong positions. I hope students who haven't made up their minds make up their minds on the subject."

The class will require a detailed research paper in which the student must argue his/her position on the matter.

"Personally I believe if you do that you reject the idea," he chuckled. "But I find sometimes that that's not the case."

MacNeill has no immediate or definite plans to continue this class in the future, claiming that he would like to do other topics such as ethics and the question of free-will. However, there is some room for compromise.

"As long as Intelligent Design is in the news, maybe it makes sense to continue to do this," MacNeill said.

Not a bad article, especially for the Sun. From all indications, it now appears that most attempts to "spin" the course in favor of intelligent design have fizzled out, and the true nature of the course is now apparent: as I have posted multiple times before, we will be reading about and discussing various concepts of purpose in nature and their relationship to evolutionary theory, including intelligent design theory. All of these concepts will be examined critically with a view toward determining which (if any) have an impact on the science of evolutionary biology, and what philosophical implications the current theory of evolution has for concepts of purpose in nature.

Not as outrageous or exciting as some of the early press reports would have you believe, but more interesting to me and (I hope) to the students who have already expressed an interest in the course.

Is Intelligent Design Distinguishable from Deism?

There is a very interesting thread at Dispatches from the Culture Wars on the difficulty (and importance) of distinguishing between deism and "intelligent design theory (IDT)." Specifically, there is a long discussion between several posters on whether IDT is fundamentally different from “theistic evolutionary theory (TET)” (which is, IMO, indistinguishable from simple deism).

In particular, several of the posters have argued that if IDT and TET are equivalent, then there is literally no science in IDT at all. That is, if God (remember, as I have posted earlier, it’s easier and more intellectually honest to type "God" than “the intelligent designer”) created the universe with just exactly the right set of natural laws that things like the bacterial flagellum could have evolved by purely natural processes alone (i.e. without further supernatural intervention), then that version of IDT is indistinguishable from deism (DEI). In that event, both would be entirely without scientific value, since both IDT and DEI would thereby accept the operation of all natural laws as both necessary and sufficient to produce all natural objects and processes.*

This means that if we are to distinguish between IDT and DEI (and, by extension, from TET) it must be incontrovertably shown that natural laws as they now exist are insufficient to produce existing natural objects and processes. As many others have pointed out, this requires proving a negative. That is, unless we assume that all currently known natural laws are literally all there are or even can be (as Lord Kelvin infamously did at the end of the 19th century), then it is possible that in the future new versions of purely natural laws will be discovered that can explain the existence of those entities now claimed to be possible only through supernatural intervention.

This, of course, leads to all kinds of logical fallacies, chief among them the problem of “supernatural incompetence.” If IDT = DEI = TET, then God is indeed omnipotent and can create natural laws that make the evolution of all natural entities possible without further intervention. In that case, IDT, DEI, and TET are indistinguishable from each other and none add anything of use to the generally accepted methods and principles of empirical science. This means that nothing more need be said about them by scientists, and we can go on doing science (including evolutionary biology) the way we have been doing up until now.

However, if IDT is not DEI nor TET, then perforce God must not be omnipotent. That is, He cannot create a set of natural laws that can in the fullness of time produce the objects and processes we observe around us.

Therefore, it seems to me that there are only two logical positions to take on this subject:**

1) God is omnipotent and therefore created the universe with natural laws of sufficient power and subtlety to allow purely natural processes to produce all natural objects (and therefore IDT is unnecessary).

or

2) God is not omnipotent and therefore cannot create a universe in which natural laws are sufficient to produce all natural objects and processes. This means that God (who is, by definition, incompetent) must intervene at specific times and places to alter nature in direct contravention of His originally created (and incompletely effective) natural laws.

These two positions have obvious and devastating implications for theology as well:

If (1) is the case, then God is only relevent to nature during it creation. From then on, He does not participate in it in any material way (and therefore prayer is useless, as all intercession by God violates His original created order), or

If (2) is the case, then God has left incontrovertable evidence of both His existence and actions in the structure of nature itself, and therefore faith is no longer necessary (and both justification and salvation through faith are pointless).

*It also seems that this version of deism is indistinguishable from what some ID theorists (including Michael Behe) are now referring to as "front-loaded" IDT (FLIDT). That is,

FLIDT = DEI = TET

all of which are irrelevent for and useless to science.

**Alert readers may notice that there is a third option: God is omnipotent, but chooses to create a universe in which His natural laws are insufficient to produce all natural objects and processes without his intervention. This strongly implies that God is either meddlesome or capricious (or both), conclusions that I suspect would not be palatable to most ID theorists, deists, or theistic evolutionists.

At the moment, my thinking is that cladistic parsimony is a special case of simplicity (if it is a case at all). But I won't make the case for that here....One thing I think we can say, from the examples, is that when we're in a situation in which we must choose among competing hypotheses or theories, and empirical evidence isn't definitive, use simplicity to make the choice.

Each of [the authors cited] urge us to run with the simplest model among the relevant alternatives unless we're forced to abandon that model for a more complicated one. What does the forcing is empirical evidence. Indeed, none of the biologists I quoted above said anything about the fact that simplicity is truth-indicative. Burnet in fact said that because the clonal theory is simplest, it's probably false! So, simplicity doesn't indicate the truth of some hypothesis or model or theory. Rather, it's a strategy that directs us toward the truth....At least we can say we've eliminated some fruitless paths of inquiry.

COMMENTARY:

I think it would be helpful to consider two possibilities vis-a-vis the application of parsimony in science:

1) Parsimony is merely "useful" in the sense that it reduces the complexity of hypotheses to a level at which they are empirically testable. When I teach my students about how science is usually done, I give them the "hypothetico-deductive" model first, and then point out that this model doesn't give you criteria for formulating testable hypotheses, it only gives you a method for testing them once they have been formulated. To formulate testable hypotheses requires an additional step: one must "mentally" test one's hypothesis to determine if:• it's empiirically testable, and• the emipirical test that one is considering can distinguish between it and alternative hypothesesIf the answers to these two questions are both "yes," then one is ready to actually run the experiment/make the observations to test the predictions that flow from the hypothesis.

In this view, parsimony is simply "useful" in that it is more likely (on average) to yield testable hypotheses whose empirical results are more likely to unambiguously validate or falsify one's predictions.

2) Parsimony might actually be an intrinsic feature of "natural causation" itself. In evolutionary psychology (my field, BTW) there is a concept known as "computational overload (CO)." Basically, CO is used as an argument against the "blank slate" hypothesis for human cognition and motivation. That is, if the mind is a "blank slate" (i.e. relies entirely on "trail and error/reinforcement" algorithms), CO rapidly overwhelms even the largest and fastest computer imagineable. Therefore, EPs like me assume that the brain is modularized, and that each module has a fairly stringent "perceptual filter" that limits inputs as a way of minimizing CO (such filters and modules having evolved by natural selection).*

The same concept could be applied to nature, and especially biology. Biological systems are fiendishly complex, much more so than physical or chemical systems. This complexity, if not minimized in some way, would result in biological systems "seizing up" as the result of CO (where "computation" is interpreted broadly as the binary and higher level interactions between multiple influences, some competing and some complementary).

Natural selection, in other words, has resulted in the evolution of biological systems in which "parsimony" has been encoded into the interactive structure of living organisms and systems of living organisms themselves, as a way of minimizing CO and maximizing effective interaction with one's environment.

Indeed, I would be tempted to argue that (1) may even be a consequence of (2), as our minds themselves are already adapted to minimizing CO, and therefore are predisposed to parsimonious solutions to problems in general, and therefore also scientific problems. In our interactions with nature as in our science, therefore, "good enough for now" is "good enough for all".--Allen

*I also suspect that this phenomenon is the basis for the "Fundamental Attribution Error (FAE)" in humans, as a predisposition for making FAEs would be selected for as long as the results of doing so were as often adaptive as deleterious (i.e. a tendency toward "false positives" in making FAEs would simply be a kind of "worse case analysis", which is almost always adaptive...especially in a dangerous world such as ours, in which even paranoids have real enemies ;-)

Monday, April 17, 2006

Teleological and Teleonomic: A New(er) Analysis

On April 17, 2006 04:35 PM David B. Benson wrote in the Panda's Thumb (scroll way down):

[Can you] explain why you state that ant colonies, cities, and other emergent organizations have purpose? In particular, what is wrong with mere teleomentalism, that an ascription of purposeful behavior is only metaphor?

Ernst Mayr [1] distinquished between two different kinds of natural processes that appear to be “goal directed”:

Teleomatic processes: Processes that simply follow natural laws, i.e. lead to a result consequential to concomitant physical forces, and the reaching of their end state is not controlled by a built-in program. The law of gravity and the second law of thermodynamics are among the natural laws which most frequently govern teleomatic processes. Examples include the cooling to ambient temperature of a red hot bar of iron and the falling of a rock to the ground.

Teleonomic processes: Processes that owe their goal-directedness to the operation of a program. The term teleonomic implies goal-direction. This, in turn, implies a dynamic process rather than a static condition, as represented by a system. Examples include the development of an adult organism from a fertilized zygote and the building of a dam by beavers.

Mayr argues very strongly that the common use of teleological language by biologists is legitimate because it recognizes the goal-directedness of biological processes. He also stresses that, although many biological processes (such as ontogeny) are clearly goal-directed, they owe their goal-directedness to the operation of programs, such as the genetic program encoded in the DNA. He concludes that although such programs themselves are goal-directed (i.e. purposeful), the process by which such programs have come into being – evolution by natural selection – is NOT itself goal directed.

[ I would state this slightly differently from Mayr: that there is no observable evidence that the evolutionary processes by which such programs come into being are goal-directed (i.e. “designed” or “purposeful”). Therefore, although such purposes may exist, they are invisible to us on principle and therefore irrelevent to scientific explanations of natural phenomena.]

Mayr concludes:

• The use of so-called teleological language by biologists is legitimate; it neither implies a rejection of physico-chemical explanation nor does it imply non-causal explanation

• At the same time, it is illegitimate to describe evolutionary processes or trends as goal-directed (teleological). Selection [reifies] past phenomena (mutation, recombination, etc.), but does NOT plan for the future, at least not in any specific way [as far as we can tell]

• Processes (behavior) whose goal-directedness is controlled by a program may be referred to as teleonomic

• Processes which reach an end state caused by natural laws (e.g. gravity, second law of thermodynamics) but not by a program may be designated as teleomatic

• Programs [of the type described above] are in part or entirely the product of natural selection

• Teleonomic (i.e. programmed) behavior occurs only in organisms (and man-made machines) and constitutes a clear-cut difference between the levels of complexity in living and in inanimate nature [i.e. they are “emergent properties” of living systems, not present in the non-living materials of which living organisms or their artifacts are composed]

• Teleonomic explanations are strictly causal and mechanistic. They give no comfort to adherents of vitalistic concepts [including supporters of “intelligent design,” if such supporters believe that the kinds of programs desctibed above come into existence as the result of a purposeful process]

• The heuristic value of the teleological Fragestellung makes it a powerful tool in biological analysis, from the study of the structural configuration of macromolecules up to the study of cooperative behavior in social systems.

COMMENTARY:

I agree with Mayr on virtually every point. In other of his publications, Mayr argues strongly for the idea that biological systems exhibit “emergent properties,” and that this is one of the primary differences between biology and the other natural sciences, such as physics. At the same time (and contra some supporters of “emergent properties,” such as Andrew North Whitehead and Teilhard de Chardin), Mayr argues very strongly for the naturalist position that such properties are well within both the darwinian paradigm and the tradition of naturalistic explanation that underlies the natural sciences.

Given the foregoing, I therefore believe that the kind of teleonomy exhibited by ants and ant colonies is indeed a natural property of such biological systems, and not just a “teleomentalism” (i.e. a semantic distinction rooted in human language and cognition, having no actual reality in nature). Furthermore, it seems to me that the kinds of advances that we have seen since Mayr wrote his paper – developments in artificial intelligence and the programming of cybernetic “expert systems”, advances in genetics, and especially a much deeper understanding of the processes of evolutionary development – lend support to Mayr’s analysis, and that using Mayr’s theoretical framework can not only assist people working in the aforementioned fields, it can also lead to some clarity in understanding the origin and evolution of purpose in nature.

This analysis leaves us with the following problem: Is the term "teleology" an umbrella term that subsumes both teleomatic and teleonomic processes, and if so, what term is most appropriate for the kinds of unambiguously goal-directed behavior exhibited by humans (and our artifacts, such as heat-seeking missiles)? My preference is to reserve the term "teleology" for the latter (i.e. clearly goal-seeking processes initiated and controlled by rational entities, such as ourselves), and apply the terms teleonomy and teleomatic the way Mayr suggests in his article.

I believe that these distinctions clearly and unambiguously distinguish between natural processes that appear to be (or even are) goal-directed, such as ontology, and processes that are not, such as natural selection and other evolutionary mechanisms.

And yes, before an ID supporter points out the obvious, the foregoing analysis doesn't eliminate the problem of evolution versus ID, since ID theorists can still argue that God (remember, I asserted a while back that I will use the proper/role name "God" instead of "the intelligent designer"...it requires fewer keystrokes and is more honest IMHO) both "designed" and "guided" the processes by which Mayr's "programs" bring about teleonomic goal-seeking behavior.

Friday, April 14, 2006

Riding the Evolution-Design Roller Coaster

[Scroll Down For Update]

This has certainly been an educational experience...but what else should one expect at Cornell? The past week has been a roller coaster of media attention, not to mention extreme reactions from both sides of the issue. What started out as an act of kindness toward an old and dear friend (my colleague and mentor, Will Provine, who was originally scheduled to teach this course), turned into a media circus, conducted almost entirely online. Here's the backstory:

For years Will Provine and I have been teaching an undergraduate seminar in the Cornell Summer Session entitled "Seminar in History of Biology." Between ourselves, we have always called the course "philosophical implications of evolution," and have always thought of it in those terms. The course description stayed the same from year to year, but the focus of the course changed, depending on what we found most interesting to discuss with our students. For the past few years, Will has focussed on the implications of evolution for the concept of human free will. When I taught the course, I focused on three topics: the implications of evolution for free will, purpose, and ethics.

Last fall, when we began talking about the focus of the course for this summer, Will (who was scheduled to teach the course) decided to focus exclusively on "intelligent design theory." Anyone who knows Will (or me, for that matter) knows that he always invites people from the opposing side to make a presentation in his course. He has debated Phillip Johnson several times, both at Cornell and Stanford, and several ID theorists (including Michael Behe and John Stanford) have made presentations in his large evolution course at Cornell. And so, since we both know the students in the Cornell IDEA Club, we planned to contact them and see if they would be interested in participating in some way in the seminar course this summer.

Then tragedy struck in Will's family, and he was unable to committ to teaching the seminar this summer. He asked me to fill in for him, and I agreed to do so. I went ahead with our plans to invite the Cornell IDEA folks to participate and submitted the course description and reading list to the department and to the Summer Session.

The Cornell IDEA Club then posted a notice on their blog about the course, pointing out that it would be a seminar in which intelligent design theory would be discussed in the larger framework of its relationship to evolutionary theory. However (perhaps because of the source), this was immediately picked up by several websites supporting ID (most notably World Net Daily) and spun as "Cornell to Offer Course in Intelligent Design."

And that was when the roller coaster crested the top of the "pull" hill and started its free roll down. The Site Meter hit counter at the bottom of my blog, which had been reading < 50 hits/day jumped to > 600 hits/hour. I was unaware of this until I glanced at it early Monday morning and was non-plussed...what in the world was happening? By Tuesday, the spin had become positively centrifugal: the course, the proposed content, the reading list, the venue, and everything else about the course (including my personal character) were being debated by literally thousands of people who knew absolutely nothing about me nor (apparently) about the course.

Luckily my Site Meter shows referrals, and so I quickly found out where most of the traffic to my site was coming from and posted much more detailed clarifications of the course, mostly for the benefit of the vast army of people who don't know me nor where I stand on the issues. The result has been very interesting: although there is less euphoria among the ID supporters, there is respect for the fact that the course is intended to be a forum for free and open discussion on the topic of purpose in nature, with ID as one of the principle examples.

But not the only one, of course. As I pointed out in the course description, the concept of purpose is one that evolutionary biologists have debated and investigated for almost two centuries. Darwin himself talked about the idea of purpose in nature, in both the Origin of Species and The Descent of Man. No less eminent an evolutionary biologist than Ernst Mayr wrote several important papers on the subject, responding to other papers by such luminaries in the field as Francisco Ayala, Colin Pittendrigh, and William Wimsat. Philosophers have also weighed in on the issue, beginning with Aristotle and including Andrew Woodfield, Ernst Nagel, and, most recently, Michael Ruse.

Most disconcerting to me were some of the early comments from evolutionary biologists, who asserted that ID should not even be mentioned in a course in evolutionary biology. Well, I not only teach a course on evolution, I also sit in on the other introductory evolution courses at Cornell and elsewhere, and ID theory is mentioned in all of them. True, it is mentioned in the context of an alternative explanation for adaptation in nature, one that is far outside the boundaries of mainstream science, but mentioned none the less.

The difference between what happens in a lecture course on evolution and what will happen this summer in the seminar course is that, rather than lecturing on the subject, I will (as always) invite the participants in the seminar to inform themselves about the subject and discuss it with as much clarity and vigor as they can muster. I believe (based on past experience) that when the cases for ID and evolutionary biology are fully and fairly made in this way, evolutionary biology will be the winner. After all, it has mountains of empirical evidence to back it up, and empirical evidence is the basis for all of science, as far as I understand it.

In answer to some of my critics from evolutionary biology, therefore, I feel that it is very appropriate for this kind of discussion to take place in a science course, rather than just a history or philosophy of biology course. Students, including science majors, are far too often not given enough credit for their ability to both formulate and judge rational arguments in a free and open forum of ideas. Despite the fact that the topic is ostensibly the philosophy of science, the debate over the validity of ID versus evolutionary theory is fundamentally a scientific debate. If scientists refuse to debate the subject, we will leave the floor open for not-quite-science, pseudoscience, and (worst of all) anti-science to claim victory, and believe me that will be what the general public perceives the ID community has achieved.

Furthermore, the paradox of purpose in nature is one that has not yet been solved by evolutionary biologists. What are evolutionary adaptations if not structural and functional characteristics that serve a purpose in the life of an organism? While it sounds silly to say that rocks fall "in order to" reach the ground, it doesn't sound silly to say that the heart pumps the blood "in order to" circulate it throughout the body. The debate over such explanations is not just semantic, and as Ernst Mayr pointed out in several articles and his book Toward a New Philosophy of Biology, focussing on the "purposefulness" of adaptations has important implications for evolutionary biology, as well as such diverse fields as cognitive psychology, epistemology, and the development of "expert" computer systems (not to mention "smart weapons" like the eminently teleological "Sidewinder" missile).

So, we shall proceed this summer, a little less naive about the "culture wars", but firmly in the belief that courteous, rational, informed discussion is the only reliable way to truth. And then, when we come to the end, we can step off the roller coaster, take a deep breath, and go look for a cotton candy stand.

UPDATE (as of Mon17Apr06@16:59EST)After a week of riding the roller coaster, several discussions stand out as representing where things were and are (and probably will be, once the course actually starts). Here they are (be sure to scroll down and read the comments):

Thursday, April 13, 2006

Evolution and Design: What Will the Course be About?

ITHACA, N.Y. (AP) — Cornell University this summer will offer a class on intelligent design, a theory that has sparked heated debate around the country on whether alternatives to evolution should be taught in public schools.

The course will include texts that oppose and support the theory of intelligent design and will be offered through the undergraduate biology program. It will be a history of biology class that looks at ethics and philosophy.

"I'm not going to be bashing (intelligent design), but I'm also not going to be advocating it," said lecturer Allen MacNeill, an evolutionary biologist who will teach the course. "I'm going to be using it — and evolutionary biology too — to think about these very complicated ideas."

Cornell President Hunter Rawlings III in an Oct. 21 speech condemned the teaching of intelligent design as science, calling it "a religious belief masquerading as a secular idea."

Intelligent design is a theory that argues that life is too complex to have developed through evolution, implying a higher power must have had a hand. It has been harshly criticized by The National Academy of Sciences and the American Association for the Advancement of Science, which have called it repackaged creationism.

Around the country, attempts to introduce public school students to alternatives to evolution such as intelligent design have largely failed.

Let me assure my faithful readers that I am not “teaching intelligent design” at Cornell Univesity this summer. Rather, I am offering a seminar course in which the participants (including me) will attempt to come to some understanding vis-a-vis the following:

As Ernst Mayr pointed out in his 1974 paper (”Teleological and Teleonomic: A New Analysis.” In Boston Studies in the Philosophy of Science, Volume XIV, pages 91 -117), it may be legitimate for evolutionary biologists to refer to adaptations as teleological. However, such adaptations have evolved by natural selection, which itself is NOT a purposeful process. Therefore, we have a fascinating paradox: purposefulness can evolve (as an emergent property) from non-purposeful matter (and energy, of course) via a process that is itself purposeless (as far as we can tell). This immediately suggests the following questions:

• Is there design or purpose anywhere in nature? • If so, are there objective empirical means by which it can be detected and its existence explained? • Can the foregoing questions be answered using methodological naturalism as an a priori assumption? • What implications do the answers to these questions have for science in general and evolutionary biology in particular?

To answer these questions, we will read several books and a selection of articles on the subject of design and purpose in nature (the course description is available here). As you can see from the reading list, we will be looking at all sides of this very challenging issue. My own position is very strongly on the side of evolutionary biology (i.e. in the tradition of “methodological naturalism”). Consequently, I disagree very strongly with the positions of Michael Behe, William Dembski, Phillip Johnson, and other representatives of the Discovery Institute. I will therefore be attacking both their positions and the metaphysical assumptions upon which they are based with as much logic and vigor as I can muster. At the same time, I have invited members of the Cornell IDEA Club to participate in the course and to explain and defend their beliefs and positions. From my previous interactions with them, I expect that they will make an equally forceful and well-argued case for their position. The students taking the course will be expected to follow the arguments, participate in them, and come to their own conclusions, which they will then be required to defend to the rest of us. Regardless of whether they agree with me or with my opponents, their work will be judged on the basis of logical coherence and marshalling of references in support of their arguments.

As to the question of whether “intelligent design theory” is worthy of study (and is especially appropriate for a science-oriented seminar course), I have several reasons to believe that it is:

First, by clearly drawing a distinction between the traditional scientific approach (i.e. “methodological naturalism”) and the “supernaturalist” approach, we can clarify just what science is capable of (and what it isn’t). Like Ernst Mayr, I believe that the question of the existence of design or purpose in nature can ultimately be answered without resort to supernatural explanations. Indeed, as an evolutionary psychologist, I believe that we do have the ability to recognize design and purpose in nature (and to act purposefully ourselves), and that this ability is the result of natural selection. That is, both of these abilities have adaptive value in a world in which some phenomena are not designed and/or purposeful and others are (the latter having potentially fatal consequences if unrecognized).

Secondly, by studying what I believe to be a flawed attempt at identifying and quantifying design or purpose in nature, we may be able to do a better job of it. Clearly, there are purposeful entities capable of “intelligent design” in the universe: I am one and I infer that you are another. There are also objects and processes that clearly are not: the air we are both currently breathing clearly fall into this class. As a scientist committed to naturalistic explanations for natural phenomena, it is clear to me that there must be some way of discerning between these two classes of objects and processes, as both of them are clearly “natural.” Therefore, we will use several approaches to the identification and explanation of design and purpose to do so.

Thirdly, the recent resurrection of “intelligent design theory” has historical and political, as well as scientific roots. By studying these, we can learn better how science proceeds, how scientific hypotheses are tested, and how scientific theories are validated (and invalidated). In my opinion, “intelligent design theory” as it is currently promulgated falls far short of the criteria for natural science, but is very useful at demonstrating how to distinguish between science and pseudoscience.

Finally, the question of design and purpose in nature is one that goes back to the foundation of western philosophy. The Ionian philosophers - Thales, Anaximander, Democritus, Epicurus, and their Roman descendant Lucretius - were the first people in recorded history to assert that nature can be explained without reference to supernatural causes. Their ideas were overshadowed by the academy of Plato and his student, Aristotle, who proposed that supernatural and teleological causes were primary. Darwin revolutionized western science because he completed the subversion of the Platonic/Aristotelian world view, replacing it with a naturalistic one much more like that of the Ionians. It is this tradition we will investigate, and which I hope we can in some way emulate this summer.

Wednesday, April 12, 2006

The Capacity for Religious Experience Is An Evolutionary Adaptation to Warfare

Given the sudden increase in readership of this list, I'm going to take the shamelessly opportunistic route and post a summary of my most recent publication: "The capacity for religious experience is an evolutionary adaptation to warfare", in Fitzduff, M. & Stout, C. (eds) (2005) The Psychology of Resolving Global Conflicts: From War to Peace, vol. 1, ch. 10, pp. 257-284. This, like the recent upsurge in interest in polygamy, is a very hot topic. Terrorism is very much in the news, and since a lot of it seems to be at least peripherally associated with extreme religious views, the idea that these can be part of an evolutionary "arms race" seems very timely.

I first gave a version of this paper at the 2004 annual conference of the New England Institute in Portland, Maine. It has since been published among the proceedings of that conference (the citation is: MacNeill, A. (2004) "The capacity for religious experience is an evolutionary adaptation to warfare" Evolution & Cognition, vol. 10, no. 1, pp. 43-60). I was later contacted by Mari Fitzduff and Chris Stout for inclusion in their anthology on peace and war, which was published last December. The latter is a terrific collection, but a little pricey (I'm glad I got a free copy out of the deal). If readers are interested, I can email a pdf of the entire paper. It's pretty good, if I do say so myself.

But why should you take just my word for it? Here's the abstract and the "core of the argument":

ABSTRACT

The criteria for deciding whether a characteristic qualifies as an evolutionary adaptation are discussed: differential survival and reproduction are considered the most appropriate criteria. The pan-specific qualities of both religious experience and warfare indicate that they are both evolutionary adaptations. There is considerable variation between individuals with respect to their capacity for religious experience and motivation to participate in warfare. Selective advantages for participation in warfare accrue to both winners and losers as long as the benefits of participation exceed the average costs. These selective advantages, primarily in the form of differential reproductive success, accrue to males when they are on the winning side in a war, and often to females no matter which side they are on.

Recent work on the evolutionary dynamics of religion have converged on a "standard model" in which religions and the supernatural entities which populate them are treated as epiphenomena of human cognitive processes dealing with the detection of and reaction to agents under conditions of stress, anxiety, and perceived threat. Religious experience at the individual level is characterized by depersonalization, coupled with submission to a super-individual force; the same is essentially the case for participation in warfare. The capacities for both religious experience and participation in warfare are adaptations insofar as they evolve by means of natural selection operating primarily at the level of individuals who are members of groups in which both kin selection and reciprocal altruism are also operative. It is likely that the overall patterns of supernatural organization exist as the result of coevolution between the memetic content of religious beliefs and the underlying neurological matrix within which such beliefs are maintained and transmitted in the context of specific ecological subsistence patterns.

THE CORE OF THE ARGUMENT

War involves violent force, up to and including killing people. To participate in a war means to participate in an activity in which there is a significant probability that one will either kill other people, or will be killed by them.

This means that any participant in warfare is faced with the possibility of painful and violent death as the result of such participation. Given this probability, if natural selection acts at the level of individuals, how can natural selection result in a propensity to participate in warfare? Clearly, either the probability that one will be killed must be perceived as low or the potential payoff from such participation must be perceived as high. If natural selection is to operate at the level of individuals, these two circumstances should ideally be obtained simultaneously,

Here is where the capacity for religious experience is crucial. By making possible the belief that a supernatural entity knows the outcome of all actions and can influence such outcomes, that one's "self" (i.e., "soul") is not tied to one's physical body, and that if one is killed in battle, one's essential self (i.e., soul) will go to a better "place" (e.g., heaven, valhalla, etc.) the capacity for religious experience can tip the balance toward participation in warfare. By doing so, the capacity for religious belief not only makes it possible for individuals to do what they might not otherwise be motivated to do, it also tends to tip the balance toward victory on the part of the religiously devout participant. This is because success in battle, and success in war, hinges on commitment: the more committed a military force is in battle, the more likely it is to win, all other things being equal. When two groups of approximately equal strength meet in battle, it is the group in which the individuals are more committed to victory (and less inhibited by the fear of injury or death) that is more likely to prevail. To give just one example, the battle cry and motto of the clan Neil has always been "Buaidh na bas!" - "Victory or death!"

Religions tell people what they most want to hear: that those agents and processes that they most fear have no ultimate power over them or pose no threat to themselves or the people they care about. In particular, by providing an intensely memorable, emotionally satisfying, and tension-releasing solution to the problem of mortality, religions make it possible for warriors to master their anxieties and do battle without emotional inhibitions. This makes them much more effective warriors, especially in the hand-to-hand combat that humans have fought throughout nearly all of our evolutionary history.

Consider the characteristics that are most often cited as central to religious experience. Newberg and d'Aquili (2001) have presented an integrated model of the neurobiological underpinnings of religious experience. They have pointed out that central to most religious experience is a sensation of awe, combined with "…mildly pleasant sensations to feelings of ecstasy." (Newberg and d'Aquili, 2001, p. 89) They have shown that such sensations can be induced by rhythmic chanting and body movements, combined with loud music and colorful visual displays, all of which produce a condition of sensory overload. This process then induces a neurological condition characterized by a sense of depersonalization and ecstatic union with one's surroundings.

This is precisely what happens as the result of military drill and training. It is no accident that humans preparing for war use exactly the same kinds of sensory stimuli described by Newberg and d'Aquili. They have tied such displays to religious activities, and shown the deep similarities between religious rituals and secular ones: "…patriotic rituals… emphasize the "sacredness" of a nation, or a cause, or even a flag…turn[ing] a meaningful idea into a visceral experience." (Newberg and d'Aquili, p. 90) The two types of activities - religious rituals and patriotic rituals - use the same underlying neurological pathways and chemistry.

Religious experience is often equated with a state of mystical union with the supernatural. But what exactly does this mean, and in the context of this presentation, is there a connection between mystical experience and warfare? The answer is almost certainly yes. That combatants have had experiences that would be classified as mystical before, during, and after battle is a simple historical fact. The Scottish flag is based on just such an experience: the white crossed diagonal bars against a field of azure of the St. Andrew's cross is said to have appeared to King Hungus and his warriors during a battle against in the Saxons. Legend says this so encouraged the Scots and frightened their adversaries that a victory was won.

A common thread in all mystical experiences is a loss of the sense of self and a union with something larger than oneself. (Newberg and d'Aquili, p. 101) Additionally, there is often a sense of submission to a higher power, in which one's personal desires and fears are subordinated to the purposes of that higher power. If that higher power were identified with the leaders of a military hierarchy, it is easy to see how such experiences could be used to increase one's loyalty and submission to that hierarchy.

Wilson (2002) has proposed that the capacity for religion has evolved among humans as the result of selection at the level of groups, rather than individuals. Specifically, he argues that benefits that accrue to groups as the result of individual sacrifices can result in increased group fitness, and this can explain what is otherwise difficult to explain: religiously motivated behaviors (such as celibacy and self-sacrifice) that apparently lower individual fitness as they benefit the group.

At first glance, Wilson's argument seems compelling. Consider the most horrific manifestation of religious warfare: the suicide bomber. A person who blows him or herself up in order to kill his or her opponents has lowered his or her individual fitness. Doesn't this mean that such behavior must be explainable only at the level of group selection? Not at all: the solution to this conundrum is implicit in the basic principles of population genetics. Recall that one of Darwin's requirements for evolution by natural selection was the existence of variation between the individuals in a population. (Darwin, 1859, pp. 7 - 59) Variation within populations is a universal characteristic of life, an inevitable outcome of the imperfect mechanism of genetic replication. Therefore, it follows that if the capacity for religious experience is an evolutionary adaptation, then there will be variation between individuals in the degree to which they express such a capacity.

Furthermore, it is not necessarily true that when an individual sacrifices his or her life in the context of a struggle, the underlying genotype that induced that sacrifice will be eliminated by that act. Hamilton's principle of kin selection (Hamilton, 1964) has already been mentioned as one mechanism, acting at the level of individuals (or, more precisely, at the level of genotypes), by which individual self-sacrifice can result in the increase in frequency of the genotype that facilitated such sacrifice. Trivers (1971) has proposed a mechanism by which apparently altruistic acts on the part of genetically unrelated individuals may evolve by means of reciprocal altruism.

Given these two mechanisms, all that is necessary for the capacity for religious behavior, including extreme forms of self-sacrifice, to evolve is that as the result of such behaviors, the tendency (and ability) to perform them would be propagated throughout a population. The removal of some individuals as the result of suicide would merely lower the frequency of such tendencies and abilities in the population, not eliminate them altogether. If by making the ultimate sacrifice, an individual who shares his or her genotype with those who benefit by that sacrifice will, at the level of his or her genes, become more common over time. (Wilson, 1975, p. 4)

Let us now consider the flip side of war: the benefits that accrue to the winners of warlike conflicts. Given the mechanisms of kin selection, one can see how warfare and the religious beliefs that facilitate it might evolve among the closely related kin groups that constitute the raiding parties characteristic of hunting/gathering and pastoral peoples. It is also possible to construct an explanation for militia warfare and professional warfare on the basis of a blend of kin selection and reciprocal altruism. However, a closer examination of the spoils of war make such explanations relatively unnecessary.

Betzig (1986) performed a cross-cultural analysis of the correlation between despotism and reproductive success in 186 different cultures. Her conclusion was that "…[n]ot only are men regularly able to win conflicts of interest more polygynous, but the degree of their polygyny is predictable from the degree of bias with which the conflicts are resolved. Despotism, defined as an exercised right to murder arbitrarily and with impunity, virtually invariably coincides with the greatest degree of polygyny, and presumably, with a correspondingly high degree of differential reproduction." (Betzig, 1986, p. 88) In other words, males who most successfully use violence and murder as a means of influencing the actions of others have historically had the most offspring. In the context of warfare, this means that the winners of a battle, or even more so, of a war will pass on to their offspring whatever traits facilitated their victory, including the capacity to believe in a supernatural force that guides their destiny and protects them in battle. The effects of such capacities are not trivial; as Betzig points out, the differences between the reproductive success of the winners of violent conflicts and the losers is measured in orders of magnitude. As noted earlier, wars are bottlenecks through which only a relative few may pass, but which reward those who do with immensely increased reproductive success.

Putting all of this together, it appears likely that the capacity for religious experience and the capacity for warfare have constituted a coevolutionary spiral that has intensified with the transitions from a hunting/gathering existence through subsistence agriculture to the evolution of the modern nation-state. As pointed out earlier, there is a correlation between the type of intergroup violence and the ecological context within which that violence occurs. Generally speaking, raiding/rustling is correlated with hunting/gathering and pastoralism, militia warfare with village agriculture, and professional warfare with urban society and the nation-state. There is a corresponding progression in the basic form of religious experience and practice: animism is most common among hunter-gatherers, while polytheism is more common among agriculturalists, and monotheism is most common in societies organized as nation-states. This is not to say there are no exceptions to this correlation. However, the fact that such a correlation can even be made points to the underlying ecological dynamics driving the evolution of subsistence patterns, patterns of warfare, and types of religious experience.

REFERENCES CITED

Betzig, L. (1986). Despotism and differential reproduction: A darwinian view of history. New York: Aldine.

Darwin, C. R. (1859). On the origin of species by means of natural selection, or the preservation of favoured races in the struggle for life. London: Murray.

Tuesday, April 11, 2006

Polygamy, De Facto and De Jure

Polygamy has suddenly entered the national consciousness, thanks to HBO's new series, Big Love. We don't have television at my house, so I haven't seen it, but the national news websites have been all over it, and generally gushing with praise. For example, the New York Times recently ran a preview of Big Love, in which the reviewer made generally positive comments about the series.

What is historically odd is that as gay marriage is gaining acceptance, the resistance to polygamy is much more powerful. Yet until this generation, gay marriage had been sanctioned by no society that we know of, anywhere at any time in history. On the other hand, polygamy was sanctioned, indeed common, in large parts of the world through large swaths of history, most notably the biblical Middle East and through much of the Islamic world.

Generally a very conservative columnist, Krauthammer's column is surprisingly non-judgmental about the series and the growing social movement for the legalization of polygamy that it reflects. Krauthammer's logic is, in my opinion, difficult to dispute:

I'm not one of those who see gay marriage or polygamy as a threat to, or assault on, traditional marriage. The assault came from within. Marriage has needed no help in managing its own long, slow suicide, thank you. Astronomical rates of divorce and of single parenthood (the deliberate creation of fatherless families) existed before there was a single gay marriage or any talk of sanctioning polygamy. The minting of these new forms of marriage is a symptom of our culture's contemporary radical individualism -- as is the decline of traditional marriage -- and not its cause.

And he's right. As I have often told my students (and usually very much to their consternation), polygyny is the accepted social norm in somewhere around 85% of all known human cultures, according to the Human Relations Area Files. Now, polygyny is what most people mistake for polygamy: that is, one male with more than one female. Polygamy simply means having more than one mate, regardless of sex. There is also polyandry, in which a female has more than one male mate, and polygynandry, in which more than one female mate with more than one male. During the past few decades, ethologists have had to become a lot more careful about how they use these terms. in particular, they now distinguish between reproductive polygamy, in which one individual mates with and produces genetically identifiable offspring with more than one mate, and social polygamy, in which the reproductively polygamous individual is behaviorally associated for extended lengths of time with each of her/his mates.

This distinction is necessary because both females and males in what appear to be monogamous relationships are, when the DNA of their offspring is tested, reproductively polygamous. The phenomenon that produces this pattern of behavior is called "extra-pair matings", and is ubiquitous among vertebrates (especially birds and mammals) and may be the overwhelmingly predominant pattern in all animals previously considered to be "monogamous." Both females and males engage in "extra-pair matings", although for somewhat different evolutionary reasons (more on this in a later post).

Which leads me to another article posted in reaction to the debut of Big Love. This one, by Jonathan Rauch, is much more negative in its evaluation of the HBO series and the social movement it reflects:

The social dynamics of zero-sum marriage are ugly. In a polygamous world, boys could no longer grow up taking marriage for granted. Many would instead see marriage as a trophy in a sometimes brutal competition for wives. Losers would understandably burn with resentment, and most young men, even those who eventually won, would fear losing. Although much has been said about polygamy's inegalitarian implications for women who share a husband, the greater victims of inequality would be men who never become husbands.

By this point it should be obvious that polygamy is, structurally and socially, the opposite of same-sex marriage, not its equivalent. Same-sex marriage stabilizes individuals, couples, communities, and society by extending marriage to many who now lack it. Polygamy destabilizes individuals, couples, communities, and society by withdrawing marriage from many who now have it.

Here is where I believe "full disclosure" is necessary, and where Rauch has been less than forthright. As this link indicates, Rauch is a gay activist whose most recent book, Gay Marriage: Why It Is Good For Gays, Good For Straights, And Good For America is a closely argued political endorsement of gay marriage from the standpoint of a gay man. His diatribe against polygamy is not so much motivated by a concern for the institution of marriage, but rather for the fact that polygamy is usually lumped together with gay marriage as "things not to be borne" by conservatives (but not, apparently, by Krauthammer). Gay activists see their hopes for legalization of gay marriage being undermined by the movement to legalize polygamy.

Which gets me to the real topic of this post. In the real world, both gay marriage and polygamy are already widespread, with or without legal recognition. Indeed, the latter is the norm in America, and probably the rest of the world as well.

Yep, you read that right: polygamy is the numerical norm, not the behavior of some religious nutcases in Utah. How can I say this? Because I've been collecting data on the subject for almost three decades. What Americans and many other people around the world call their marriage system is monogamy. However, in reality it is serial monogamy; that is, most people are married to more than one person during their lifetime, but in series rather than simultaneously. Serial monogamy is the predominant form of marriage in the United States, and has been for several decades.

What my research has indicated is that serial monogamy isn't monogamy at all; as I tell my students, "if it's 'serial', it may be breakfast food, but it sure ain't monogamy." From the standpoint of reproductive success (the ultimate criterion for evolution by natural selection), having offspring with more than one mate is polygamy, regardless of whether one has them in sequence or simultaneously. What my research has shown so far is that approximately half of all of the people in my study cohort have been divorced at least once (with slightly more females than males being divorced):

Among those who have divorced, there is a striking asymmetry between the ages and reproductive successes of females and males. That is, males remarry approximately twice as often as females, and have significantly more children than females who do not remarry. Furthermore, the average age difference between females and males decreases in females with second marriages (from about three years to a year and a half), whereas the age differences between females and males increases dramatically in males with second and subsequent marriages (from about a year and a half to greater than eight years):

in other words, when females remarry (which they do much less often than males), they marry a male closer to their age than their first husband. By contrast, when males remarry, (which they do several times, according to my study), they marry a female significantly younger than they are, and this difference increases with each subsequent marriage.

More interesting still is the differences in the number of children per individual:

Females have an average of 1.74 offspring with their first husbands, but only 0.03 with their second (in my study, the number of females marrying more than twice was too small to include in the sample). By contrast, males who have 1.73 offspring with their first wives, have 0.30 offspring with their second wives (i.e. ten times as many), and 0.03 offspring with their third wives (again, the number of males marrying more than three times was too small to include in my study).

What does all this mean? If one considers cumulative numbers of offspring, it means that males who divorce and remarry have almost twice the overall reproductive success of females who do so:

This asymmetry is striking, and argues very strongly for a biologically based cause for the differences in mating patterns in females and males.

I should hasten to add that I haven't submitted the results of this study for publication yet. One problem with it as it currently stands is that the sample size (less than 300 individuals so far) isn't large enough to draw definite conclusions about American society as a whole. Furthermore, as several people who have seen the data have pointed out, my figures seriously underestimate the degree to which such asymmetries may actually exist. The reason for this underestimate is that (for practical reasons having to do mostly with ease of data collection) I have limited my analysis to legal marriages and divorces. As most people are aware, the frequency of cohabitation in the United States is very large and still growing. If I were to include "extra-legal relationships" and breakups, and include the data from those that result in the production of offspring, I'm fairly confident that the patterns I've found so far would be even more significant.

So, what are we to conclude from all this? Several things:• The "undermining" of traditional marriage has been done by married people, not gays nor polygamists• The average person in America is already a de facto polygamist• The political movement to legalize polygamy, like the movement to legalize gay marriage, will continue to grow as more and more people realize the logic of the movement and its application to their own lives

It is clear to me that we will not return to the "golden age" of traditional heterosexual monogamy, not as long as people are allowed to live their lives in private without excessive governmental interference. Somewhere around the turn of the 20th century something changed in American life, something that set in motion the transition through which we are currently passing. That transition accelerated following the two world wars of the 20th century, and shows every sign of accelerating today. That we will eventually reach some new equilibrium in these behaviors is virtually certain. What that new equilibrium will be is anybody's guess.

COURSE DESCRIPTION: This seminar addresses, in historical perspective, controversies about the cultural, philosophical, and scientific implications of evolutionary biology. Discussions focus upon questions about gods, free will, foundations for ethics, meaning in life, and life after death. Readings range from Charles Darwin to the present (see reading list, below).

The current debate over "intelligent design theory" is only the latest phase in the perennial debate over the question of design in nature. Beginning with Aristotle's "final cause," this idea was the dominant explanation for biological adaptation in nature until the publication of Darwin's Origin of Species. Darwin's work united the biological sciences with the other natural sciences by providing a non-teleological explanation for the origin of adaptation. However, Darwin's theory has been repeatedly challenged by theories invoking design in nature.

The latest challenge to the neo-darwinian theory of evolution has come from the "intelligent design movement," spearheaded by the Discovery Institute in Seattle, WA. In this course, we will read extensively from authors on both sides of this debate, including Francisco Ayala, Michael Behe, Richard Dawkins, William Dembski, Phillip Johnson, Ernst Mayr, and Michael Ruse. Our intent will be to sort out the various issues at play, and to come to clarity on how those issues can be integrated into the perspective of the natural sciences as a whole.

In addition to in-class discussions, course participants will have the opportunity to participate in online debates and discussions via the instructor's weblog. Students registered for the course will also have an opportunity to present their original research paper(s) to the class and to the general public via publication on the course weblog and via THE EVOLUTION LIST.

INTENDED AUDIENCE: This course is intended primarily for students in biology, history, philosophy, and science & technology studies. The approach will be interdisciplinary, and the format will consist of in-depth readings across the disciplines and discussion of the issues raised by such readings.

PREREQUISITES: None, although a knowledge of evolutionary theory and philosophy of biology would be helpful.

DAYS, TIMES, & PLACES: The course will meet on Tuesday and Thursday evenings from 6:00 to 9:00 PM in Mudd Hall Room 409 (The Whittaker Seminar Room), beginning on Tuesday 27 June 2006 and ending on Thursday 3 August 2006. We will also have an end-of-course picnic at a location TBA.

CREDIT & GRADES: The course will be offered for 4 hours of credit, regardless of which course listing students choose to register for. Unless otherwise noted, course credit in BioEE 467/B&Soc 447 can be used to fulfill biology/science distribution requirements and Hist 415/S&TS 447 can be used to fulfill humanities distribution requirements (check with your college registrar's office for more information). Letter grades for this course will be based on the quality of written work on original research papers written by students, plus participation in class discussion.

COURSE ENROLLMENT & REGISTRATION: All participants must be registered in the Cornell Six-Week Summer Session to attend class meetings and receive credit for the course (click here for for more information and to enroll for this course). Registration will be limited to the first 18 students who enroll for credit. Auditors may also be allowed, space permitting (please contact the Summer Session office for permission to audit this course).

Wednesday, April 05, 2006

Accuracy, Precision, Nominalism, and Occam's Razor

Robert Skipper has a new blog in which he discusses (among other things) the concept of simplicity in science (also called the principle of parsimony). In it he discusses the importance of "Occam's Razor," named for the English logician (and Franciscan monk) William of Ockham. Skipper then goes on to provisionally define "simplicity" in scientific explanations as "paucity of parameters," and defends this interpretation from several different perspectives, including empiricism, Baysian inference, computationalism, and that of individual selectionism a la Coyne, Barton, and Turelli (1997) [1].

He concludes that the application of Ockham's razor doesn't necessarily produce "truth," but is a necessary part of an investigative procedure that does:

[Evolutionary biologists] urge us to run with the simplest model among the relevant alternatives unless we're forced to abandon that model for a more complicated one. What does the forcing is empirical evidence. Indeed, none of the biologists I quoted above said anything about the fact that simplicity is truth-indicative....So, simplicity doesn't indicate the truth of some hypothesis or model or theory. Rather, it's a strategy that directs us toward the truth....At least we can say we've eliminated some fruitless paths of inquiry.

I have a problem with this analysis, specifically with the idea that science (properly applied, and including Occam's Razor) gets us closer and closer to "truth." The problem, as I see it, has to do with the idea that "truth" exists independently of our pursuit of it, in the same way that a target exists independently of an archer who is trying to hit it. From this viewpoint, science is to "truth" what practice is to the archer; it is that method by which we get closer to hitting some independently existing "truth."

Don't get me wrong: I'm not arguing for solipsism here. Yes, indeed, I believe (without proof, BTW) that nature exists independently of our ability to describe or analyze it...that is, I'm a naturalist through and through, at least as far as grounding my thinking in non-solipsistic metaphysics is concerned. However, I make a distinction between nature and our descriptions/analyses of it; science is the latter. In the same way, I believe that there is a fundamental distinction that must be made between what actually exists in nature and what science can describe/analyze about it. And I believe that this difference can be captured in understanding the difference between "accuracy" and "precision".

Consider the example of the archer and her target once again. The name for the phenomenon that she is honing via practice is "accuracy." Accuracy is the point for an archer: as an archer practices shooting, she hits closer and closer to the gold, and consequently we would say that her accuracy improves – her shooting is becoming more accurate through practice.

By contrast, our archer could become more precise: that is, her shots could become more tightly clustered, but not necessarily in the gold. As an archer myself, I find that my precision is already pretty good - my shots all hit pretty close to the same place. Hitting the target then involves compensating for whatever is causing my precision to veer from the target. That is, I am trying to "map" my actual precision onto some theoretical "accuracy."

As the foregoing description implies, accuracy is a teleological process, whereas precision need not be. A machine that doesn't aim at all can be very precise, missing a target in exactly the same way every time. Only a goal-oriented entity can be accurate, as aiming for a target is inherently teleological.

So, is science goal-directed (i.e. is it teleological)? Of course it is; however, is our "aim" a more accurate or a more precise description/analysis of nature (or both)? I believe that, in general, we are doing pretty well if we can manage precision. After all, most statistical tests can't distinguish between the two (Bayesian inference is an exception); that's what hypothesis-spinning and experimental design is all about. We try to design our investigations so that we get precise data that we can then apply to a description/analysis of nature that we believe is accurate.

But this all leads to a problem, one that I have alluded to before: the problem of Platonic idealism. To believe that accuracy is possible is to believe that ideal forms are "real" and that we can get closer and closer to describing/analyzing them. From this viewpoint, scientists who believe (like Robert Skipper apparently does) that our descriptions of nature are coming closer and closer to some ideal "truth" are therefore Platonic idealists.

As I pointed out in an earlier post to this list ("On the Origin of the Specious"), this problem is most acute in biological taxonomy. Believing that there really are such things as "species" is a form of Platonic idealism. That this is so is easily demonstrated: simply ask any taxonomist to explain what a "type specimen" is. S/he will tell you that this is the "ideal" example of a member of that species (usually the first one classified and stored in a collection somewhere) against which all new specimens of that species are checked to determine if they are members of the same species.

Ernst Mayr railed against "typological thinking," and yet biology (including evolutionary biology) is shot through with it. And where typology lurks, teleology is close behind. Is it any wonder that the vast majority of people (including many scientists) would agree with the statement that organisms reproduce "in order to ensure the survival of the species?" A more egregious misrepresentation of the adaptiveness of reproduction would be difficult to formulate, and yet most people would simply nod their heads in agreement with such a statement.

Why? Because most people (including most scientists) are, whether they realize it or not, "idealists" in the Platonic sense. From this viewpoint, organisms do what they do "in order to ensure the survival of" the ideal form of their "species," regardless of any benefit or cost to themselves as individuals. Individuals don't matter, in other words; the "target" is the "survival of the species."

But, as I have asserted before, "species" don't really exist. They are literally a figment of the human imagination...or rather, a by-product of the human tendency toward teleological idealism. Look outside: do you see any "species?" I see trees, bushes, grasses, a couple of crows...but nowhere are there any "species" in view. I can learn that the trees and bushes and grasses and crows that look very similar to each other can be thought of as members of particular "species," but that is quite literally a thought : I infer upon these individual things imaginary categories that I refer to as "trees," "bushes," "grasses," and "crows."

As I have stated before, Darwin's most subversive idea was that the variation between individual organisms (which provides the raw material for natural selection) is real, irreducible, and the basis for (to quote Wallace) "the tendency for variations to depart indefinitely from the original type." If the "original type" were "real," then variations from it wouldn't matter. Furthermore, if we think about "species" as being "real," then descent with modification becomes a kind of "blind archery" in which the "species" is "shooting" into the future toward becoming some other "species."

This way of thinking is entirely human, and entirely without empirical foundation. And, perhaps not accidentally, William of Ockham had a solution to this problem. His solution was to break fundamentally from Platonic idealism: to adopt a viewpoint about reality known as nominalism. To a nominalist, the names we invent for objects and processes that appear similar/the same are only names: they are not real. The only real things are individual objects and processes. True, there are similarities between them that we can recognize – indeed, we "re-cognize" them - we "re-think" them in our minds. Science is that process by which we identify and systematically analyze such patterns of similarity, which we codify into "scientific theories/laws." When we do so, we somewhat unintentionally reify those similarities of appearance/behavior as "natural laws/processes" and believe that we have come closer to somehow "hitting" the "truth."

If the history of science has shown us anything, however, it is that when we think we are closest to the "truth" we are furthest from reality. Lord Kelvin infamously proclaimed that 19th century physicists had discovered virtually everything there was to know about physical reality. He did so only a few years before Einstein swept away the foundations of 19th century physics (perhaps this is why, a century later, so many neo-Platonists still can't countenance Einstein and the new physics he spawned). The real joy (and, to some, the real terror) of science is that as far as we can tell, there is no end to the game, and the more precise our descriptions become, the more absolute "truth" seems to "softly and suddenly vanish away."